数据库可以为每个节点分配顺序号，这样就知道每个节点的位置，可以在常数时间内比较两个节点的文档顺序。
The database can assign sequence Numbers to each node so that it knows the position of each node and can compare the document order of two nodes in constant time.
我来把更一般的形式，写出来吧，在一维空间中，位置和速度，作为时间函数的，一般形式，这里的加速度是一个常数。
I now would like to write down, in most general form the equation for the position and the velocity as a function of time for a one-dimensional motion whereby the acceleration is constant.
相反，在宇宙中，该常数会随所在的位置发生变化。
Rather, it seems to vary from place to place within the universe.
应用推荐